Abstract

Adhesion is the essential prerequisite for the pathogenesis of bacterial and fungal infections because the micro-organisms must adhere to host mucosal cells in order to multiply and create colonies before specific symptoms allow the disease to be detected. This is particularly true in the case of female urogenital infections such as urinary tract infections, bacterial vaginosis and vaginitis. It has been reported that tymol, a component of thyme essential oil, has interesting antimicrobial effects on various micro-organisms and can interact with adhesiveness, a major determinant of bacterial and fungal virulence. It significantly reduces Escherichia coli adhesion to human vaginal epithelial cells
(VECs) at concentrations ranging from 1/2 MIC to 1/32 MIC, and that of Staphylococcus aureus at concentrations ranging from 1/2 MIC to 1/16 MIC. Candida albicans is particularly capable of adhering to VECs endothelial cells, soluble factors and extracellular matrix, but its incubation
with thymol reduces its adhesion to VECs with a significant linear relationship from 1/2 MIC to 1/8 MIC.
Phenolic compounds such as thymol also play an important role as a result of their anti-oxidant activity. During respiratory bursts and the killing of micro-organisms, neutrophils generate reactive oxygen species whose release
can induce oxidative stress and tissue injury. The use of luminol amplified chemiluminescence has shown that thymol incubated with human neutrophils significantly reduces oxidative bursts down to 2.73 µg/ml, a very low concentration. Together with the other findings concerning bacterial and fungal adhesion, the antioxidant activity of thymol is useful for the strategy of protecting
against vaginosis or vaginitis using new compounds other than antibiotics or antimycotics, because the presence in only one molecule of antibacterial, antifungal and anti-oxidant activities may have sinergistic effects.